Suspensions and diluents for metronidazole and baclofen

ABSTRACT

Suspensions of metronidazole or baclofen and/or salts or ester derivative thereof, such as metronidazole benzoate, are disclosed. The suspension may include metronidazole or baclofen, and/or a salt or ester derivative thereof a hydrocolloid stabilizer, simethicone emulsion, a buffer, such as sodium citrate, (dihydrate), a preservative, a thickening agent, a sweetener, and water.

RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 ofInternational Patent Application Serial No. PCT/US2017/050714, filedSep. 8, 2017, entitled “SUSPENSIONS AND DILUENTS FOR METRONIDAZOLE ANDBACLOFEN”, which claims the benefit of U.S. Provisional No. 62/385,325filed on Sep. 9, 2016, the entire contents of each of which areincorporated by reference herein.

BACKGROUND OF THE INVENTION

Medications are often prescribed in a solid dosage form which manypatients are unable to swallow, requiring these medications to beadministered in an oral liquid form. The populations unable to swallowsolid dosage forms and are in need of liquid formulations includepediatric patients, older patients with dysphagia, ICU patients andpatients on enteral nutrition.

SUMMARY OF THE INVENTION

Disclosed herein are suspensions of metronidazole or baclofen and/orsalts thereof. The suspensions may comprise metronidazole or baclofen ora salt thereof, such as metronidazole benzoate, a hydrocolloidstabilizer, simethicone emulsion, sodium citrate, (dihydrate), apreservative, a thickening agent, a sweetener, and water. In someembodiments, the suspension comprises metronidazole or baclofen. In someembodiments, the hydrocolloid stabilizer is microcrystalline celluloseand/or carboxymethylcellulose sodium. In one embodiment, thehydrocolloid stabilizer is Avicel RC591. In some embodiments, thethickening agent is xanthan gum.

A variety of sweeteners and flavorings can be used to improvepalatability of the disclosed formulations. In some embodiments, thesweetener is one or more of ammonium glycyrrhizate, sucralose, andsaccharin sodium. In some embodiments, the formulation comprises flavorgrape 59.266/A. In some embodiments, the preservative is sodium benzoateand/or citric acid.

In some aspects of the invention, the pH of the formulation is between3.6 and 4.6. In other aspects of the invention, the pH of theformulation is 3.4 and 4.0, 3.0-4.0, 3.0-5.0, or 3.0-6.0. In someembodiments, the formulation retains homogeneity of less than +/−5% ofassay for active pharmaceutical ingredient after at least 30 days, atleast 40 days, at least 45 days, at least 60 days, at least 75 days, atleast 100 days, each up to alternatively 100 days, 200 days, 1 year ortwo years. In other embodiments, the formulation retains homogeneity ofless than +/−10% of assay for active pharmaceutical ingredient after atleast 30 days, at least 40 days, at least 45 days, at least 60 days, atleast 75 days, at least 100 days, each up to alternatively 100 days, 200days, 1 year or two years. In some embodiments the homogeneity isassessed for samples stored at room temperature.

One embodiment of the liquid formulations as taught by the inventioncomprises ammonium glycyrrhizate (magnasweet 100), Avicel RC591, citricacid (anhydrous), grape flavor, saccharin sodium, simethicone emulsion,sodium benzoate, sodium citrate, sucralose, xanthan gum, and water.

In a specific embodiment a liquid formulation of the inventioncomprises:

a. 0.05000% (w/v) ammonium glycyrrhizate, (magnasweet 100);

b. 1.500% (w/v) Avicel RC591;

c. 0.500% (w/v) citric acid, (anhydrous);

d. 0.0500% (w/v) flavor grape 59.266/A;

e. 0.0300% (w/v) saccharin sodium;

f. 0.2000% (w/v) simethicone emulsion, (30%);

g. 0.1500% (w/v) sodium benzoate;

h. 0.2000% (w/v) sodium citrate, (dihydrate);

i. 0.1000% (w/v) sucralose;

j. 0.1000% (w/v) xanthan gum;

k. purified water.

Another embodiment of the liquid formulations as taught by the inventioncomprises citric acid, D&C Yellow No. 10, FD&C Red No 40, grape flavor,hydroxyethyl cellulose, propylene glycol, simethicone emulsion, sodiumbenzoate, sucralose, and water.

In a specific embodiment a liquid formulation of the inventioncomprises:

a. 0.12% (w/v) citric acid, (anhydrous);

b. 0.0002% (w/v) D&C Yellow No. 10;

c. 0.000038% (w/v) FD&C Red No. 40;

d. 0.0500% (w/v) flavor grape 59.266/A;

e. 0.5000% (wv) hydroxyethyl cellulose;

f. 5.000% (w/v) propylene glycol;

g. 0.1500% (w/v) simethicone emulsion, (30%);

h. 0.1000% (w/v) sodium benzoate;

i. 0.2000% (w/v) sucralose;

j. purified water.

In some embodiments a liquid formulation of the invention comprises0.12-0.6% (w/v) citric acid; 0.1500-0.250% (w/v) simethicone emulsion;0.1000-0.1550% (w/v) sodium benzoate; sweetener and water.

Disclosed herein are diluents for reconstituting metronidazole orbaclofen or a salt thereof. In some embodiments, the liquid diluentcomprises 0.03-0.08% (w/v) ammonium glycyrrhizate; 1.0-2.0% (w/v) AvicelRC591; 0.1-0.9% (w/v) citric acid; 0.01-0.10% (w/v) flavoring;0.01-0.05% (w/v) saccharin sodium; 0.1-0.3% (w/v) simethicone emulsion;0.1-0.2% (w/v) sodium benzoate; 0.1-0.3% (w/v) sodium citrate,(dihydrate); 0.05-0.2% (w/v) sucralose; 0.05-0.2% (w/v) xanthan gum; andpurified water.

In a specific embodiment, the liquid diluent comprises 0.05% (w/v)ammonium glycyrrhizate, (magnasweet 100); 1.50% (w/v) Avicel RC591;0.50% (w/v) citric acid, (anhydrous); 0.05% (w/v) flavor grape 59.266/A;0.03% (w/v) saccharin sodium; 0.2% (w/v) simethicone emulsion, (30%);0.15% (w/v) sodium benzoate; 0.20% (w/v) sodium citrate, (dihydrate);0.10% (w/v) sucralose; 0.10% (w/v) xanthan gum; and purified water.

Further disclosed herein are suspensions of metronidazole or baclofen ora salt thereof, comprising metronidazole or baclofen or a salt ofmetronidazole or baclofen;

simethicone emulsion; sodium bicarbonate; and sodium citrate,(dihydrate), where the suspension is stable for at least 30 days whenstored at 2-8 or 15-30 degrees celsius. In some embodiments, thesuspension is stable for at least 30 days when stored at 38-42 degreescelsius. In some embodiments, the suspension comprises a pH of no morethan pH 4.6, 5.5, or 6.5. In some embodiments, the suspension comprisesa pH of 4.

In some embodiments, the formulations described herein retainhomogeneity of less than +/−2%, +/−5%, or +/−10% of assay for activepharmaceutical ingredient after at least 30 days, 60 days or 90 days. Insome embodiments, the formulations described herein maintain homogeneityof the active pharmaceutical ingredient at room temperature for at least30 days, at least 40 days, at least 45 days, at least 60 days, at least75 days, at least 100 days, each up to alternatively 100 days, 200 days,1 year or two years after reconstitution. In some embodiments theformulations described herein maintain homogeneity of the activepharmaceutical ingredient for 30 days-two years 40 days-two years, 90days-two years, 1-2 years, 1½ years-2 years or up to 2 years.

In any of the metronidazole suspensions described herein the suspensionmay be prepared with micronized metronidazole.

In some aspects the invention is a suspension of baclofen or a saltthereof, that includes baclofen or a salt thereof; a hydrocolloidstabilizer, simethicone emulsion; sodium citrate, (dihydrate); apreservative, a thickening agent, a sweetener, and water.

In some embodiments the hydrocolloid stabilizer is microcrystallinecellulose and/or carboxymethylcellulose sodium. In other embodiments thethickening agent is xanthan gum. In other embodiments the pH of theformulation is between 3.6 and 4.6. In yet other embodiments theformulation retains homogeneity of less than +/−5% or less than +/−10%or any percentage there between of assay for active pharmaceuticalingredient after at least 30 days.

In a specific embodiment a liquid formulation of the invention comprisesbaclofen plus:

-   -   0.05000% (w/v) ammonium glycyrrhizate, (magnasweet 100);    -   1.500% (w/v) Avicel RC591;    -   0.500% (w/v) citric acid, (anhydrous);    -   0.0500% (w/v) flavor grape 59.266/A;    -   0.0300% (w/v) saccharin sodium;    -   0.2000% (w/v) simethicone emulsion, (30%);    -   0.1500% (w/v) sodium benzoate;    -   0.2000% (w/v) sodium citrate, (dihydrate);    -   0.1000% (w/v) sucralose;    -   0.1000% (w/v) xanthan gum;    -   purified water.

A suspension of baclofen, comprising a salt of baclofen; simethiconeemulsion; sodium bicarbonate; and sodium citrate, (dihydrate), whereinthe suspension is stable for at least 30 days when stored at 2-8 degreescelsius is provided in other aspects of the invention.

In some embodiments the suspension comprises a pH of no more than pH4.6. In other embodiments the formulation retains homogeneity of lessthan +/−5% of assay for active pharmaceutical ingredient after at least60 days.

Each of the embodiments of the invention can encompass variousrecitations made herein. It is, therefore, anticipated that each of therecitations of the invention involving any one element or combinationsof elements can, optionally, be included in each aspect of theinvention.

DETAILED DESCRIPTION

The invention encompasses liquid compounded formulations ofmetronidazole or baclofen and salts or ester derivatives thereof such asmetronidazole benzoate, diluents that can be used by a pharmacist toreconstitute metronidazole or baclofen or a salt or ester derivativethereof, and related compounding kits. In some embodiments, theinvention encompasses liquid compounded formulations of metronidazole orbaclofen, diluents that can be used by a pharmacist to reconstitutemetronidazole or baclofen, and related compounding kits.

Commonly, pediatric and geriatric populations encounter difficulty beingadministered solid oral dosage forms such as capsules and tablets whichmay lead to noncompliance with the recommended pharmacotherapy with thesolid oral dosage forms and likely results in rendering the therapyineffective. Solid oral dosage forms are usually not favorable forpediatric and geriatric populations due to the potential risk ofchoking. Additionally, certain solid oral dosage forms of medicationscannot be administered simply by crushing (e.g., patients requiringvarious types of feeding tubes) because of the coating or drug deliverymechanism by which the drug is released.

For most community pharmacies (retail/chain and independent), compendialmetronidazole oral formulations do not provide ease of use, flavoring,flexible dosing, or a uniform formulation. Commercially available dosageforms include many gels, lotions, tablets, capsules, and solutions forinjections, including 170 marketing authorizations currently recognizedin the United States by the U.S. National Library of Medicine, DailyMedlisting, however none of these are liquids for oral dosing.

The liquid formulations of the invention is stable for at least 30 days,at least 40 days, at least 45 days, at least 60 days, at least 75 days,at least 100 days, each up to alternatively 100 days, 200 days, 1 year,or two years or for 30 days-two years 40 days-two years, 90 days-twoyears, 1-2 years, 1½ years-2 years or up to 2 years. under roomtemperature storage conditions. The liquid formulations of the inventionhave improved palatability compared to the compendial formulation, andwhen compared to previously described oral formulations or compoundedformulations. The liquid formulations disclosed herein have improvedhomogeneity when compared to commercially available liquid formulations.

Metronidazole is an antibiotic and antiprotozoal drug with a broad rangeof indications, many of which require or benefit from oral dosing,including bone and joint infections, endocarditis, various gynecologicinfections, intra-abdominal infections, meningitis, and other CNSinfections, infections of the respiratory tract, septicemia, infectionsof the skin and skin structure, amebiasis, bacterial vaginosis,Balantiadiasis, Blastocystis hominis infection, Clostridiumdifficile-associated diarrhea (CDAD) and associated conditions, Crohn'sDisease, including refractory perianal Crohn's Disease, infection byDientameoba fragilis, infection by Dracunculus medinensis (Guinea Worm),giardiasis, Helicobacter pylori infection and associated duodenal ulcerdisease, non-gonococcal urethritis, pelvic inflammatory disease,Rosacea, infection by Clostridial bacteria, especially C. tetani, andtrichomoniasis.

In addition, metronidazole can be used as perioperative prophylaxiswhere there is a risk of anaerobic bacterial infection, for example incolorectal surgery or appendectomy. Furthermore, metronidazole is usedas a component of anti-infective, post-exposure prophylaxis in sexualassault victims. In many of these conditions, patients may, as a resultof the conditions, or as a result of comorbidities, have difficulty intaking drug, or be unwilling or unable to take drug in tablet or capsulepresentations. The disclosed liquid formulations provide clinicians andpatients with convenient and palatable alternative dosing formats thatallow precise adjustment of dose, and enhance patient compliance withclinician orders.

In specific patient populations, such as those with hepatic impairment,a clinician may need to adjust the dose of metronidazole and monitorserum concentrations to balance therapeutic benefit against risk insubjects with reduced liver function. The liquid formulations disclosedherein provide clinicians with a tool to make fine adjustments to oraldosing is such patients. Similarly, in geriatric patients, theage-related changes in the pharmacokinetics of metronidazole can requireclinicians to adjust dosage. The liquid formulations disclosed hereinprovide clinicians with a tool to make fine adjustments to oral dosingis such patients in order to maximize therapeutic benefit while managingpatient risk in a way that cannot be efficiently achieved by dosing withfractional tablets or capsules.

Baclofen (β-(4-chlorophenyl)-GABA) is a muscle relaxer and anantispastic agent that is often used to treat muscle symptoms caused bymultiple sclerosis, including spasm, pain, and stiffness. Baclofen actson the central nervous system to relieve spasms, cramping, and tightnessof muscles caused by spasticity. It is a GABA receptor agonist(derivative of γ-aminobutyric acid (GABA)) that acts specifically on theGABA-B receptors. Baclofen is believed to block mono-and-polysynapticreflexes by acting as an inhibitory neurotransmitter, blocking therelease of excitatory transmitters.

The liquid formulations disclosed herein maintain stability andhomogeneity for at least thirty days. With respect to stability, samplesof the disclosed formulations show greater than 90%, or greater than95%, or greater than 97.5% of the nominal concentration or startingconcentration of metronidazole when measured in an assay compliant withthe assay for Metronidazole benzoate, thirty days after the liquid isformulated. Alternately, when assayed thirty days after the liquid isformulated, samples average to greater than 90%, or greater than 95%, orgreater than 97.5%, or greater than 98%, or greater than 99% of thenominal concentration or starting concentration of metronidazole orbaclofen. With respect to homogeneity, samples of the disclosedformulations taken from the top, middle, and bottom of the container offormulated drug show greater than 90%, or greater than 95%, or greaterthan 97.5% of the nominal concentration or starting concentration ofmetronidazole, when measured in an assay compliant with the assay formetronidazole or baclofen thirty days after the liquid is formulated.Alternately, when assayed thirty days after the liquid is formulated,samples taken from the top, middle, and bottom of the container offormulated drug show less than 10%, less than 5%, less than 2%, lessthan 1% or less than 1% but greater than 0.5% variation from each other,or from the average concentration measured thirty days after formulationor from the nominal concentration of metronidazole or baclofen.

An advantage of the invention is the flexibility of dose that can beprescribed by the physician. The ability to reconstitute metronidazoleor baclofen or a salt or ester derivative thereof, in a liquidformulation to be dosed orally to a patient later in the day, over thecourse of several days, over the course of a week, or over the course ofseveral weeks, provides ease of use to the compounding pharmacist,physician, and patient. This provides a time saving and cost effectivemethod of producing multiple drug doses in the pharmacy for a singlepatient. In addition, as the method described utilized bulk API ratherthan recycling final dosage forms of licensed drug products (i.e.recovering granules of drug from drug capsules) the invention providesadditional consistency over alternative compounding formulation methods.In some embodiments, the formulations described and the preparationmethods disclosed produce comparably stable and homogenous liquidformulations from more than one source of bulk API, demonstrating thebroad applicability of the methods disclosed.

The ability to use the liquid formulations of the invention also offersadvantages to physicians, as it provides the ability to prescribe withmore flexibility for a range of challenging and otherwise vulnerablepatients. The palatability of the disclosed formulations improvespatient compliance and minimizes patient distress. The liquid nature ofthe formulations disclosed allows the dosing of metronidazole orbaclofen and salts or ester derivatives thereof, to children who areunable to reliably swallow capsules. In addition, the liquid nature ofthe formulations disclosed allows the dosing of metronidazole orbaclofen and salts or ester derivatives thereof, to elderly patients whoare unable to reliably swallow capsules. Furthermore, the liquid natureof the formulations disclosed allows the dosing of metronidazole orbaclofen to critical care patients who are otherwise unable to swallowcapsules due to intubation or other injuries, pathologies, orinterventions that inhibit the ability to receive or take medication insolid format.

The liquid formulations disclosed provide a vehicle for the delivery ofa suspension of metronidazole or baclofen or salts or ester derivativesthereof, within a diluent comprising microcrystalline cellulose,simethicone emulsion, a buffer system (for example sodium bicarbonateand/or sodium citrate), one or more preservatives, one or morethickening agents, one or more sweeteners and/or flavorings, and water.While not excluding the possibility that other ingredients contribute tothe stability of the formulation, microcrystalline cellulose and/orcarboxymethycellulose sodium are included to stabilize the activeingredient. Similarly, the use of simethecone contributes to stabilityby minimizing the formation of foam on mixing or agitation duringformulation, or incidentally during transport, use, and storage. Theformation of foam could be associated with conditions denaturing the APIor conditions that would diminish the patient's ability to measure anexact dose. sodium bicarbonate and/or sodium citrate can be used toprovide a buffered diluent that promotes the maintenance of a constantpH during liquid storage after formulation. Thickening agents andsweeteners are included to improve the handling, appearance, andpalatability of the finished dosage.

Other buffers that can be used in the suspensions and diluents describedherein include pharmacologically acceptable combinations of cationsselected from sodium, potassium, magnesium, calcium, and aluminum andanions selected from bicarbonate, hydroxide, gluconate, glycinate, andother appropriate amino acid salts. Additional buffering agents caninclude other forms of citrate, tartrates, acetates, carbonates,phosphates, metaphosphates, glycerophosphates, polyphosphates,pyrophosphates, and certain oxides in pharmacologically andpharmaceutically acceptable combinations of anions and cations providingbuffering capacity as known in the art.

Preservatives that can be used in the formulations disclosed hereininclude anti-microbials, anti-oxidants, and agents providing biocidal orbiostatic activity, such that a low bioburden is maintained in theformulation of the invention from preparation through storage, andduring routine use by patients and clinicians. Exemplary preservativesinclude benzyl alcohol or other pharmaceutically acceptable alcohol,ascorbic acid, ascrobyl palmitate or other pharmaceutically acceptableascorbate salts, BHA, BHT, citric acid or other citrate salts, sodiumbenzoate, benzoic acid or other pharmaceutically acceptable benzoatesalts, sodium bisulfate, sodium metabisulfite, sodium sulfite, parabens,potassium sorbate or other pharmaceutically acceptable sorbate salts, orvanillin.

Sweeteners or sweetening agents may include any compounds that provide asweet taste to enhance the palatability of the formulation, includingnatural and synthetic sugars and natural and synthetic sweeteners (i.e.,non-sugar sweetening agents). These could include glucose, fructose,sucrose, or other pharmaceutically acceptable monosaccharide anddisaccharides or sugar alcohols, such as xylitol. Also, sweeteners mayinclude maltodextrin, polydextrose and the like. Other sweeteners mayinclude glycerin, inulin, maltol, salts of acesulfame, alitame,aspartame, neotame, cyclamate salts, saccharin and its salts, and otherartificial and naturally-occurring agents providing sweetness eithersingly or in combination.

In other embodiments, the liquid formulations comprise a flavoring agentor flavorant to enhance the flavor or aroma of the dose, and to improvegeneral palatability of the dose, thus helping to mask the flavor of themetronidazole or baclofen, or salt or ester derivative thereof, activeingredient which patients may find unpleasant. This provides an improvedexperience for patients, and better compliance with the drug regimendesired by clinicians. Suitable natural or artificial flavors can beselected from pharmaceutically acceptable options as described instandard pharmacy references which are known to those skilled in theart. In a particular embodiment, grape flavor is used. The use of grapeflavor has been found to be effective in helping to mask the unpleasantflavor of metronidazole or baclofen and salts or ester derivativesthereof. Natural and synthetic flavors can be used and adapted to thepalate of diverse patient populations, including but not limited to,age- and culturally-related flavor preferences (for example bubble gumflavor for pediatric patients).

In further embodiments, the liquid formulation may contain apharmaceutically acceptable coloring agent. Many such agents areapproved for use by the U.S. Food and Drug Administration, and are wellknown to those skilled in the art of compounding pharmacy. The use ofcolor can enhance the aesthetic appearance of the dose as well asproviding confirmation of the identity of the drug in a context wheremore than one oral formulation is being prepared, stored, transported,or used. Enhancing the aesthetic appearance of the dose increased theoverall palatability of the dose, which provides benefits to patientsand clinicians in terms of improved patient experience and improvedcompliance with the drug regimen. The ability to unambiguously identifythe medication in the pharmacy, clinical, and patient context providesbenefits to the patient by reducing the scope for errors in thepreparation, storage, handling, transport, and use of the medication. Inaddition, the use of color in the formulations can mask color changes inthe formulation lacking additional color agents. For example, uncoloredformulations may change color due to chemical changes taking placeduring storage that do not affect the safety, potency, or efficacy ofthe medication, but that might confuse a patient or clinician, or thatmight lead to a lack of compliance with a prescribed drug regimen.

A key problem in devising oral liquid formulations that are practical,safe, and effective to make and use, is the balance required betweenpalatability and the handling requirements of the dose form on the onehand, and the stability of the formulation and the homogeneity of thedoses on the other. Where, as in the present invention, it is desired toproduce a liquid medication for oral delivery in a series of dosesspread over time, it is critical to provide a formulation in which thepotency of the API remains acceptably constant over the time that theformulation is to be used, so that from the first dose to last dose, thesame dose of active drug is delivered per unit volume of the formulationdosed to the patient. In addition, as in the case of the presentinvention where the API is presented as a suspension in a liquidformulation, it is necessary that the formulation is capable ofproviding homogenous doses. That is, that the API does not clump, settleto the bottom, float to the top, or stick to the sides of the containeror any dosing or manufacturing device in a manner that would cause thedose of API contained in unit volume doses obtained from the preparationto vary unacceptably. It is generally desirable for the formulation tobe sufficiently pleasant for the patient to consume and assurecompliance with the regimen prescribed by the clinician, where the doseis delivered orally. It is generally desirable for the viscosity of theliquid formulation to be low enough to facilitate handling of theformulation in the manufacture, storage, and dosing in a manner suchthat there are not unacceptable losses of drug, i.e., material adheringto the containers or equipment used for manufacture and storage or byadherence or clumping within the drug delivery device such as anasogastric feeding tube. If too much drug adheres to and clumps onequipment and containers used to make, store, and deliver doses, thenthe delivery of API to the patient becomes unreliable, which underminesthe consistency, efficacy, and safety of therapy.

Specific examples are provided below of pharmaceutically acceptableformulations that achieve appropriate homogeneity and stability inuseful, practical, and palatable presentations.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one skilled in the art.Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice of testing of embodimentsdescribed herein, certain preferred methods, devices, and materials arenow described.

As used herein, active pharmaceutical ingredient (or “API”) refers tometronidazole or baclofen and/or a salt or ester derivative thereof, forexample, metronidazole benzoate.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural reference unless the context clearly dictatesotherwise. Thus, for example, reference to “an excipient” is a referenceto one or more excipients and equivalents thereof known to those skilledin the art, and so forth.

The term “about” is used to indicate that a value includes the standardlevel of error for the device or method being employed to determine thevalue. The use of the term “or” in the claims is used to mean “and/or”unless explicitly indicated to refer to alternatives only or thealternatives are mutually exclusive, although the disclosure supports adefinition that refers to only alternatives and to “and/or”. The terms“comprise”, “have”, and “include” are open-ended linking verbs. Anyforms or tenses of one or more of these verbs “comprises,” “comprising,”“has,” “having,” “includes,” and “including” are also open-ended. Forexample, any method that “comprises,” “has” or “includes” one or moresteps is not limited to possessing only those one or more steps and alsocovers other unlisted steps.

“Optional” or “optionally” may be taken to mean that the subsequentlydescribed structure, event or circumstance may or may not occur, andthat the description includes instances where the events occurs andinstances where it does not.

As used herein, the term “therapeutic” means an agent utilized to treat,combat, ameliorate, prevent or improve an unwanted condition or diseaseof a patient. In some embodiments, a therapeutic agent is a bactericide,amebicide or trichomonacide. In some embodiments the therapeutic agentdirect anti-inflammatory effects, effects on neutrophil motility, effecton lymphocyte transformation, and effects on cell-mediated immunefunction. In some embodiments the therapeutic agent is bactericidal orbacteriostatic against gram positive anaerobes and gram negativeanaerobes. In some embodiments the therapeutic agent is active againstHelicobacter pylori, Entamoeba hystolytica, Trichomonas vaginalis,Giardia lambalia, or Balantidium coli.

As used herein, the terms “patient,” “subject” and “individual” areintended to include living organisms in which certain conditions asdescribed herein can occur. Examples include humans, monkeys, cows,sheep, goats, dogs, cats, mice, rats, and transgenic species thereof. Ina preferred embodiment, the patient is a primate. In certainembodiments, the primate or subject is a human. In certain instances,the human is an adult. In certain instances, the human is a child. Incertain instances, the human is elderly. Other examples of subjectsinclude experimental animals such as mice, rats, dogs, cats, goats,sheep, pigs, and cows.

By “pharmaceutically acceptable”, it is meant the carrier, diluent orexcipient must be compatible with the other ingredients of theformulation and not deleterious to the recipient thereof.

The term “pharmaceutical composition” shall mean a compositioncomprising at least one active ingredient, whereby the composition isamenable to investigation for a specified, efficacious outcome in amammal (for example, without limitation, a human). Those of ordinaryskill in the art will understand and appreciate the techniquesappropriate for determining whether an active ingredient has a desiredefficacious outcome based upon the needs of the artisan.

A “therapeutically effective amount” or “effective amount” as usedherein refers to the amount of active compound or pharmaceutical agentthat elicits a biological or medicinal response in a tissue, system,animal, individual or human that is being sought by a researcher,veterinarian, medical doctor or other clinician, which includes one ormore of the following: (1) preventing the disease; for example,preventing a disease, condition or disorder in an individual that may bepredisposed to the disease, condition or disorder but does not yetexperience or display the pathology or symptomatology of the disease,(2) inhibiting the disease; for example, inhibiting a disease, conditionor disorder in an individual that is experiencing or displaying thepathology or symptomatology of the disease, condition or disorder (i.e.,arresting further development of the pathology and/or symptomatology),and (3) ameliorating the disease; for example, ameliorating a disease,condition or disorder in an individual that is experiencing ordisplaying the pathology or symptomatology of the disease, condition ordisorder (i.e., reversing the pathology and/or symptomatology). As such,a non-limiting example of a “therapeutically effective amount” or“effective amount” of a composition of the present disclosure may beused to inhibit, block, or reverse the activation of gastric acidsecretion.

The terms “treat,” “treated,” “treatment,” or “treating” as used hereinrefers to both therapeutic treatment in some embodiments andprophylactic or preventative measures in other embodiments, wherein theobject is to prevent or slow (lessen) an undesired physiologicalcondition, disorder or disease, or to obtain beneficial or desiredclinical results. For the purposes described herein, beneficial ordesired clinical results include, but are not limited to, alleviation ofsymptoms; diminishment of the extent of the condition, disorder ordisease; stabilization (i.e., not worsening) of the state of thecondition, disorder or disease; delay in onset or slowing of theprogression of the condition, disorder or disease; amelioration of thecondition, disorder or disease state; and remission (whether partial ortotal), whether detectable or undetectable, or enhancement orimprovement of the condition, disorder or disease. Treatment includeseliciting a clinically significant response without excessive levels ofside effects. Treatment also includes prolonging survival as compared toexpected survival if not receiving treatment. A prophylactic benefit oftreatment includes prevention of a condition, retarding the progress ofa condition, stabilization of a condition, or decreasing the likelihoodof occurrence of a condition. As used herein, “treat,” “treated,”“treatment,” or “treating” includes prophylaxis in some embodiments.

Various aspects of the embodiments described above may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing, and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

The present invention is further illustrated by the following Examples,which in no way should be construed as further limiting. The entirecontents of all of the references (including literature references,issued patents, published patent applications, and co-pending patentapplications) cited throughout this application are hereby expresslyincorporated by reference.

EXAMPLES Example 1

An exemplary formulation of a liquid diluent of the present inventionwas prepared. In order to make a relative high viscosity formulationwith approximately 255 cP viscosity in a preparation at batch size of 2liters, the following method was successfully used. For referencepurposes, this formulation is referenced herein as Formula 6 in someembodiments.

-   -   1. 1700 mL of purified water, was added to a suitable container.    -   2. 30.0 grams of Avicel RC-591 was added while mixing the        preparation.    -   3. 2.00 grams of xanthan gum, was added to the preparation while        continuing to mix.    -   4. The preparation was mixed for 30 to 60 minutes.    -   5. 1.00 grams of ammonium glycyrrhizate, (also known as        magnasweet 100) was added to preparation while continuing to        mix.    -   6. 0.600 grams of saccharin sodium, was added to the preparation        while continuing to mix.    -   7. 4.00 grams of sodium citrate, (dihydrate) was added to the        preparation while continuing to mix.    -   8. 3.00 grams of sodium benzoate, was added to the preparation        while continuing to mix.    -   9. 2.00 grams of sucralose, was added to the preparation while        continuing to mix.    -   10. Mixing was continued for 10 to 20 minutes.    -   11. 10.0 grams of citric acid, (anhydrous) was added to the        preparation while continuing to mix.    -   12. 4.00 grams of simethicone emulsion, (30%) was added to the        preparation while continuing to mix.    -   13. 1.00 grams of flavor grape 59.266/A was added to the        preparation while continuing to mix.    -   14. Mixing was continued for 10 to 20 minutes.    -   15. The mixing was stopped and sufficient purified water, was        added to make the final volume up to 2000 mL.    -   16. The diluent was mixed for a further 10-15 minutes.    -   17. The batch was transferred to containers using bottle        B325-38-BLA-WHT and cap 8040-A.

Properties of the diluent, an off-white liquid with a grape odor, weredetermined. The dynamic viscosity (30 RPM at 25° C.) was found to be 255cP, the density was found to be 1.01 g/mL, and the pH was 3.72 at 25.1°C.

Example 2

Physicochemical properties and data characterizing the stability andhomogeneity of metronidazole formulated to 50 mg/ml and 100 mg/mL in theliquid diluent described above as Formula 6 were determined. Suspensionsproduced with micronized versus non-micronized metronidazole werecompared. The metronidazole suspension was prepared using a suspensionkit at 40° C. and 75% RH. The suspension was then stored at 25° C. and60% RH for an extended period of time. Samples were tested for stabilityafter 15 and 30 days of storage. The concentration of the API(metronidazole benzoate) in samples obtained from the top, middle(meaning midway between the surface of the liquid and the bottom of thecontainer) and bottom of the container containing the formulated drugwere measured. The metronidazole assay was run on a HPLC with samples of5.00 μL, for 18 minutes. The data for the 50 mg/ml suspension producedfrom micronized metronidazole is shown in Table 1 and the data for the100 mg/mL suspension produced from micronized metronidazole is shown inTable 2.

TABLE 1 Time Point: Kits Initial Initial Initial Initial Initial 3 MPull Date: Kits for Compounding N/A N/A N/A N/A N/A Time Point:Compounded Solution (in-use) Testing Method Specification Initial 15days 30 days 60 days 90 days Initial Appearance of ATM- A slightly Aslightly A slightly A slightly Suspension 1095 hazy, white hazy,slightly hazy, slightly hazy, slightly to slightly yellow liquid yellowliquid yellow liquid yellow liquid with a grape with a grape with agrape with a grape odor odor odor odor pH USP<791> Report 3.7  3.7 3.7Results Assay USP 90.0%- Top: 97.9% 97.9% Top: 97.2% 110.0% of Middle:98.2% Middle: 97.4% label claim Bottom: 98.1% Bottom: 97.1%

TABLE 2 Time Point: Kits Initial Initial Initial Initial Initial 3 MPull Date: Kits for Compounding N/A N/A N/A N/A N/A Time Point:Compounded Solution (in-use) Testing Method Specification Initial 15days 30 days 60 days 90 days Initial Appearance of ATM- A slightly Aslightly A slightly A slightly Suspension 1095 hazy, white hazy,slightly hazy yellow hazy, slightly to yellow yellow liquid liquid witha yellow liquid liquid with a with a grape grape odor with a grape grapeodor odor odor pH USP<791> Report 3.7  3.7 3.7 Results Assay USP 90.0%-Top: 95.2% 95.5% Top: 94.3% 110.0% of Middle: 95.3% Middle: 95.5% labelclaim Bottom: 94.9% Bottom: 94.5%

In contrast to the micronized metronidazole the data for a 50 mg/mlsuspension produced from non-micronized metronidazole is shown below.The non-micronized metronidazole benzoate still shows a gradient fromthe top to the bottom. The suspensions were stored at 25±2° C./60±5% RH.

Metronidazole Benzoate Suspension Assay Results Using Non-MicronizedMetronidazole

Time Point Sample Assay Average RSD Initial Top 99.6% 109.9% 8.3% Middle113.3% Bottom 116.9%

Example 3

Physicochemical properties and data characterizing the stability andhomogeneity of baclofen formulated to 1 mg/ml and 5 mg/mL in the liquiddiluent described above as Formula 6 were determined. Suspensions wereproduced at a 2 oz or 4 oz sample size using several baclofen batchesand the relative stability with storage time was compared. The baclofensuspension was prepared using a suspension kit at 40° C. and 75% RH. Thesuspension was then stored at 25° C. and 60% RH for an extended periodof time. Samples were tested for stability after 15, 30, and 60 days ofstorage. The concentration of the API in samples obtained from the top,middle (meaning midway between the surface of the liquid and the bottomof the container) and bottom of the container containing the formulateddrug were measured. The baclofen assay was run on a HPLC with samples of5.00 μL for 18 minutes. The data for the 1 mg/ml suspension produced ina 4 oz sample using different batches of baclofen is shown in Tables 3and 4 respectively and the data for the 5 mg/mL suspension produced in a4 oz or 2 oz sample is shown in Tables 5 and 6 respectively.

TABLE 3 Time Point: Kits Initial 3 M Pull Date: Kits for Compounding N/AN/A N/A N/A Time Point: Compounded Solution (in-use) Testing MethodSpecification Initial 15 days 30 days 60 days Initial Appearance of ATM-A slightly A slightly A slightly A slightly A slightly Suspension 1095hazy, white hazy, white hazy, white hazy, white hazy, white liquid witha liquid with a liquid with a liquid with a liquid with a grape odorgrape odor grape odor grape odor grape odor Assay USP 90.0%- Top: 96.7%97.4% Top: 97.2% 97.2% 110.0% of Middle: 97.0% Middle: 96.8% label claimBottom: 96.7% Bottom: 96.8% pH USP<791> Report N/A  3.8 3.8  3.8 results

TABLE 4 Time Point: Kits Initial Initial Initial Initial 3 M Pull Date:kits for Compounding N/A N/A N/A N/A Time Point: Compounded Solution(in-use) Testing Method Specification Initial 15 days 30 days 60 daysInitial Appearance of ATM- A slightly A slightly A slightly A slightly Aslightly Suspension 1095 hazy, white hazy, white hazy, white hazy, whitehazy, white liquid with a liquid with a liquid with a liquid with aliquid with a grape odor grape odor grape odor grape odor grape odorAssay USP 90.0%- Top: 95.9% 97.3% Top: 97.1% 97.6% 110.0% of Middle:96.5% Middle: 96.7% label claim Bottom: 96.6% Bottom: 95.8% pH USP<791>Report N/A  3.8 3.8  3.8 results

TABLE 5 Time Point: Kits Initial Initial Initial Initial 3 M Pull Date:Kits for Compounding N/A N/A N/A N/A Time Point: Compounded Solution(in-use) Testing Method Specification Initial 15 days 30 days 60 daysInitial Appearance of ATM- A slightly A slightly A slightly A slightly Aslightly Suspension 1095 hazy, white hazy, white hazy, white hazy, whitehazy, white liquid with a liquid with a liquid with a liquid with aliquid with a grape odor grape odor grape odor grape odor grape odorAssay USP 90.0%- Top: 101.7% 100.9% Top: 101.1% 101.7% 110.0% of Middle:102.5% Middle: 100.7% label claim Bottom: 100.9% Bottom: 103.8% pHUSP<791> Report N/A  4.0 4.0  4.0 results

TABLE 6 Time Point: Kits Initial Initial Initial Initial 3 M Pull Date:Kits for Compounding N/A N/A N/A N/A Time Point: Compounded Solution(in-use) Testing Method Specification Initial 15 days 30 days 60 daysInitial Appearance of ATM- A slightly A slightly A slightly A slightly Aslightly Suspension 1095 hazy, white hazy, white hazy, white hazy, whitehazy, white liquid with a liquid with a liquid with a liquid with aliquid with a grape odor grape odor grape odor grape odor grape odorAssay USP 90.0%- Top: 98.0% 96.8% Top: 97.0% 96.9% 110.0% of Middle:98.3% Middle: 97.1% label claim Bottom: 96.8% Bottom: 97.1% pH USP<791>Report N/A  4.0 4.0  4.0 results

The diluent of the invention produced highly superior stability of themetronidazole and baclofen suspensions.

The foregoing written specification is considered to be sufficient toenable one skilled in the art to practice the invention. The presentinvention is not to be limited in scope by examples provided, since theexamples are intended as a single illustration of one aspect of theinvention and other functionally equivalent embodiments are within thescope of the invention. Various modifications of the invention inaddition to those shown and described herein will become apparent tothose skilled in the art from the foregoing description and fall withinthe scope of the appended claims. The advantages and objects of theinvention are not necessarily encompassed by each embodiment of theinvention.

Example 4

An exemplary liquid formulation present invention was prepared. Forreference purposes, this formulation is referenced herein as FormulaR9990, in some embodiments.

Methods for preparing the formulation can be found below:

-   -   1. 5 L of colorant solution was prepared in a suitable        container.    -   2. 400.0 grams of sucralose was prepared in a suitable        container.    -   3. 200.0 grams of sodium benzoate, was added to the preparation        while continuing to mix.    -   4. 240.0 grams of citric acid, was added to the preparation        while continuing to mix.    -   5. 1000.0 grams of Baclofen, was added to the preparation while        continuing to mix.    -   6. 10000.0 grams of propylene glycol was transferred into a        suitable container and 1000.0 grams of hydroxyethyl cellulose        was added. The mixture was then added to the preparation while        continuing to mix.    -   7. 300.0 grams of simethicone emulsion was added to the        preparation while continuing to mix.    -   8. The preparation was mixed for 30 to 60 minutes.    -   9. The colorant solution was added to the preparation while        continuing to mix.    -   10. 100.0 grams of flavor grape 59.266/A was added to the        preparation while continuing to mix.

Physicochemical properties and data characterizing the stability of thebaclofen solution 1 mg/ml and baclofen suspension 5 mg/mL using FormulaR9990 above were determined. Suspensions were produced at a 4 oz or 10oz sample size and the relative stability with storage time wascompared. The stability data for the 1 mg/ml solution produced in a 10oz sample at 38-42 degrees Celsius is shown in Tables 7 and the data forthe 5 mg/mL suspension produced in a 4 oz sample at 38-42 degreesCelsius is shown in Tables 8.

TABLE 7 Time Point: Testing Method Specification Initial 1 M Appearanceof Organoleptic A slightly hazy, A slightly hazy, A slightly hazy,Solution yellow to orange yellow to orange white liquid with liquid withliquid with a grape odor a grape odor a grape odor Baclofen AssayIn-house 90.0%-110.0% of label 100% 100% claim Sodium Benzoate In-house80.0%-120.0% of label 101% 101% Assay claim pH USP<791> Report results4.0 4.0 Density In-house Report results 1.00 1.00

TABLE 8 Time Point: Testing Method Specification Initial 1 M Appearanceof Organoleptic A slightly hazy, A slightly hazy, A slightly hazy,Solution yellow to orange yellow to orange white liquid with liquid withliquid with a grape odor a grape odor a grape odor Baclofen AssayIn-house 90.0%-110.0% of label 101% 102% claim Sodium Benzoate In-house80.0%-120.0% of label 102% 102% Assay claim pH USP<791> Report results4.2 4.3 Density In-house Report results 1.00 1.01

1. A suspension of metronidazole or a salt or ester derivative thereof,comprising metronidazole or a salt or ester derivative thereof; ahydrocolloid stabilizer, simethicone emulsion; sodium citrate,(dihydrate); a preservative, a thickening agent, a sweetener, and water.2. The suspension of claim 1, wherein the hydrocolloid stabilizer ismicrocrystalline cellulose and/or carboxymethylcellulose sodium.
 3. Thesuspension of claim 1, wherein the thickening agent is xanthan gum. 4.The suspension of claim 1, wherein the suspension comprisesmetronidazole benzoate.
 5. The suspension of claim 1, wherein thesweetener is selected from the group consisting of ammoniumglycyrrhizate, sucralose, and saccharin sodium.
 6. The suspension ofclaim 1, wherein the preservative is sodium benzoate.
 7. The suspensionof claim 1, wherein the preservative is citric acid.
 8. The suspensionof claim 1, further comprising flavor grape 59.266/A.
 9. The suspensionof claim 1, wherein the pH of the formulation is between 3.6 and 4.6.10. The suspension of claim 1, wherein the formulation retainshomogeneity of less than +/−5% of assay for active pharmaceuticalingredient after at least 30 days.
 11. The suspension of claim 1,wherein the suspension includes the following: a. 0.05% (w/v) ammoniumglycyrrhizate, (magnasweet 100); b. 1.50% (w/v) Avicel RC591; c. 0.50%(w/v) citric acid, (anhydrous); d. 0.05% (w/v) flavor grape 59.266/A; e.0.03% (w/v) saccharin sodium; f. 0.2% (w/v) simethicone emulsion, (30%);g. 0.15% (w/v) sodium benzoate, NF; h. 0.20% (w/v) sodium citrate,(dihydrate); i. 0.10% (w/v) sucralose; j. 0.10% (w/v) xanthan gum; andk. purified water,
 12. The suspension of claim 1, wherein the suspensionincludes the following: a. 0.12% (w/v) citric acid, (anhydrous); b.0.0002% (w/v) D&C Yellow No. 10; c. 0.000038% (w/v) FD&C Red No. 40; d.0.0500% (w/v) flavor grape 59.266/A; e. 0.5000% (wv) hydroxyethylcellulose; f. 5.000% (w/v) propylene glycol; g. 0.1500% (w/v)simethicone emulsion, (30%); h. 0.1000% (w/v) sodium benzoate; i.0.2000% (w/v) sucralose; j. purified water.
 13. A liquid diluentcomprising: 0.03-0.08% (w/v) ammonium glycyrrhizate; 1.0-2.0% (w/v)Avicel RC591; 0.1-0.9% (w/v) citric acid; 0.01-0.10% (w/v) flavoring;0.01-0.05% (w/v) saccharin sodium; 0.1-0.3% (w/v) simethicone emulsion;0.1-0.2% (w/v) sodium benzoate; 0.1-0.3% (w/v) sodium citrate,(dihydrate); 0.05-0.2% (w/v) sucralose; 0.05-0.2% (w/v) xanthan gum; andpurified water.
 14. The liquid diluent of claim 12, comprising: 0.05%(w/v) ammonium glycyrrhizate, (magnasweet 100); 1.50% (w/v) AvicelRC591; 0.50% (w/v) citric acid, (anhydrous); 0.05% (w/v) flavor grape59.266/A; 0.03% (w/v) saccharin sodium; 0.2% (w/v) simethicone emulsion,(30%); 0.15% (w/v) sodium benzoate; 0.20% (w/v) sodium citrate,(dihydrate); 0.10% (w/v) sucralose; 0.10% (w/v) xanthan gum; andpurified water.
 15. A suspension of metronidazole, comprising a salt orester derivative of metronidazole; simethicone emulsion; sodiumbicarbonate; and sodium citrate, (dihydrate), wherein the suspension isstable for at least 30 days when stored at 2-8 degrees celsius.
 16. Thesuspension of claim 1, wherein the suspension comprises a pH of no morethan pH 4.6.
 17. The suspension of claim 1, wherein the formulationretains homogeneity of less than +/−5% of assay for activepharmaceutical ingredient after at least 30 days.
 18. The suspension ofclaim 1, wherein the formulation maintains homogeneity of the activepharmaceutical ingredient for at least 30 days after reconstitution.19-28. (canceled)
 29. A liquid diluent comprising: citric acid;flavoring; hydroxyethyl cellulose; simethicone emulsion; propyleneglycol; sodium benzoate; sucralose; and purified water.